/Engine/Source/Runtime/Experimental/Animation/Constraints/Public/TransformConstraint.h
Returns a delegate that can be used to monitor for property changes. This can be used to monitor constraints changes only instead of using FCoreUObjectDelegates::OnObjectPropertyChanged that is listening to every objects. Note that bScaling is currently the only property change we monitor but this can be used for other properties.
typedef TMulticastDelegate_TwoParams< void, [UTickableTransformConstraint](API\Runtime\Constraints\UTickableTransformConstraint) *, const [FPropertyChangedEvent](API\Runtime\CoreUObject\UObject\FPropertyChangedEvent) & > FOnConstraintChanged